Roofing Terms Glossary

Reference This Handy List of Common Roofing Terms to Get a Better Understanding of the Many Components That Make up Your Roofing System



Rooftop fungus that can leave dark stains on roofing

Angled fasteners

Roofing nails and staples driven into decks at angles not parallel to the deck


American Plywood Association - Tests and sets standards for all varieties of plywoods used in the U.S

Apron flashing

Metal flashing used at chimney fronts


Asphalt Roofing Manufacturer’s Association - Organization of roofing manufacturers


A bituminous waterproofing agent used in various types of roofing materials

Asphalt concrete primer

Asphalt based primer used to prepare concrete and metal for asphalt sealant

Asphalt plastic cement

Asphalt based sealant material, meeting ASTM D4586 Type I or II. Used to seal and adhere roofing materials. Also called mastic, blackjack, roof tar, bull


The American Society for Testing and Materials - Organization that sets standards for a wide variety of materials, including roofing



Granular material added to shingle’s back to assist in keeping separate during delivery and storage


Blistering is bubbles or pimples in roofing materials - usually moisture related. In shingles, blisters are either moisture under the material or moisture trapped inside the material.


When shingles are subjected to high winds, and are forced off a roof deck


When a wrinkle or ripple affects shingles or their underlayments


Closed-cut valley

A shingle valley installation method where one roof plane’s shingles completely cover the other’s. - the top layer is cut to match the valley lines.


GAFMC’s respected brand name for ventilation products


When rust, rot or age negatively affect roofing metals


The metal or siding material that is installed over roof-top base flashing systems

Country Mansion® & Country Estates™

GAFMC’s limited lifetime warranty shingle


A peaked water diverter installed behind chimneys and other large roof projections - effectively diverts water around projections


When shingles are improperly installed over an existing roof or are over-exposed, they form a curl, or "cup."



The substrate over which roofing is applied - usually plywood, wood boards, or planks


A raised roof extending out of a larger roof plane


An installed lip that keeps shingles up off of the deck at edges, and extends shingles out over eaves and gutters, and prevents water from backing up under shingles

Dubl-Coverage® Mineral Guard

Roll roofing material with 19" selvage edge for double-coverage over roof deck



The roof edge from the fascia to the structure’s outside wall - in general terms, the first three feet across a roof is termed the eave


When installing rolled products in roofing, the area where a roll ends on a roof, and is overlapped by the next section of rolled material (underlayments, rolled roofing)


The area on any roofing material that is left exposed to the elements



Nails or staples used in securing roofing to the deck


The Federal Housing Authority - Sets construction standards throughout the U.S.

Fiberglass mat

Fibers condensed into strong, resilient mats for use in roofing materials


Metal pan extending up or down a roof slope around flashing pieces - usually at chimneys and plumbing vents


Materials used to waterproof a roof around any projections through the roof deck

Flashing cement

Sealant designed for use around flashing areas, typically thicker than plastic cement


Gable roof

Traditional roof style; two peaked roof planes meeting at a ridge line of equal size


GAFMC cant strips for deflecting water away from flashing areas - typically used on low slope roofs

Golden Pledge®

GAFMC’s strongest limited warranty for shingles - America’s strongest steep-slope warranty

Grand Sequoia®

GAFMC shingle with wood shake appearance

Grand Slate™

GAFMC shingle with slate appearance


Crushed rock that is coated with a ceramic coating and fired, used as top surface on shingles



The method to assure sealing of shingles on very steep slopes, in high wind areas, and when installing in cold weather

High nailing

When shingles are nailed or fastened above the manufacturer’s specified nail location

Hip legs

The down-slope ridges on hip roofs

Hip roof

A roof with four roof planes coming together at a peak and four separate hip legs


Ice Dam

When a snow load melts on a roof and re-freezes at the eave areas - ice dams force water to "back-up" a roof and cause leakage


"L" flashing

Continuous metal flashing consisting of several feet of metal used at horizontal walls, bent to resemble an "L"

Laminated shingles

Shingles made from two separate pieces that are laminated together - GAFMC Timberline® Series, Country Mansion® and Grand Sequoia® Shingles - also called dimensional shingles and architectural shingles


The area where roll roofing or rolled underlayments overlap one another during application (see also side laps and end laps)

Low slopes

Roof pitches less than 4/12 are considered low sloped roofs - special installation practices must be used on roofs sloped 2/12-4/12



 A roof design with a nearly vertical roof plane that ties into a roof plane of less slope at its peak


The general term for the base material of shingles and certain rolled products

Modified bitumen

Rolled roofing membrane with polymer modified asphalt and either polyester or fiberglass reinforcement


Mixture of sand, mortar, limestone and water used in bonding a chimney’s bricks together



Painted line on laminated shingles, to aid in the proper placement of fasteners


When a nail is not fully driven, it sits up off the roof deck


Installing a second layer of shingles aligning courses with the original roof to avoid shingle cupping


The National Roofing Contractors Association - Respected national organization of roofing contractors


Open valley

Valley installation using metal down the valley center

Organic mat

Material made from recycled wood pulp and paper

Organic Shingle

Shingles made from organic (paper) mats


Oriented Strand Board - A decking made from wood chips and lamination glues


The term used for fasteners driven through roofing material with too much force, breaking the material


Installing shingle courses higher than their intended exposure



Pitch-ratio of the rise of the roof to the span of the roof

Power vents

Electrically powered fans used to move air from attics and structures

Plastic cement

Asphalt based sealant - also called bull, mastic, tar, asphalt cement

Plumbing vents

Term used to describe plumbing pipes that project through a roof plane - also called vent stacks

Prevailing wind

The most common direction of wind for a particular region


Quarter sized

Term for the size of hand sealant dabs, size of a U.S. 25¢ piece



Method of installing shingles in a straight up the roof manner

Rake edge

The vertical edge of gable style roof planes

Release film

The plastic sheet installed on the back of Weather Watch® and StormGuard® underlayments - Used for packaging and handling, remove before installation

Rigid vent

Hard plastic ridge vent material

Roof louvers

Rooftop rectangular shaped roof vents - also called box vents, mushroom vents, airhawks, soldier vents

Roof plane

A roofing area defined by having four separate edges - one side of a gable, hip or mansard roof



The exposed section of double thickness on Timberline® Series shingles - shaped to imitate wood shake look on the roof


Sealant installed on shingles - after installation, heat and sun will activate sealant to seal the shingles to each other


The non exposed area on rolled roofing - area without granules, designed for nail placement and sealant

Shed roof

Roof design of a single roof plane - area does not tie into any other roofs


GAFMC’s shingle underlayment - breather type with fiberglass backing to reduce wrinkles and buckles


The area on rolled material where one roll overlaps the rolled material beneath it - also called selvage edge on rolled roofing


Where a vertical roof plane meets a vertical wall - the sides of dormers etc.

Soffit ventilation

Intake ventilation installed under the eaves, or at the roof edge

Smart Choice® Limited Warranty

GAFMC’s standard shingle limited warranty

Smart Choice® System Plus Limited Warranty

GAFMC’s next grade of enhanced warranty - extended coverage for owners

Starter strip

The first course of roofing installed - usually trimmed from main roof material

Steep slope roofing

Generally all slopes higher than 4/12 are considered steep slopes


Metal flashing pieces installed at side-walls and chimneys for weather-proofing


GAFMC waterproof underlayment - film surfaced rolled underlayment, 1.5 squares coverage per roll



The bottom portion of traditional shingle separated by the shingle cut-outs


Removal of existing roofing materials down to the roof deck


When shingles reflect the uneven surface beneath them - shingles installed over buckled shingles may show some buckles

Timberline® Series

GAFMC’s trademark name for laminated wood shake style shingles


GAFMC enhanced Hip and Ridge Shingles


When a roof plane ties into another roof plane that has a different pitch or slope



Term used to describe a fastener not fully driven flush to the shingles surface


Asphalt based rolled materials designed to be installed under main roofing material, to serve as added protection



Area where two adjoining sloped roof planes intersect on a roof creating a "V" shaped depression


Term used to describe moisture laden air


The term used in roofing for the passage of air from an enclosed space


Warm wall

The finished wall inside of a structure, used in roofing to determine how to install waterproof underlayments at eaves


The written promise to the owner of roofing materials for material related problems

Waterproof underlayments

Modified bitumen based roofing underlayments - designed to seal to wood decks and waterproof critical leak areas

Weather Stopper® Integrated Roofing System™

GAFMC’s complete roofing system and components

Weather Watch®

GAFMC’s granule surfaced waterproof underlayment

Woven Valleys

The method of installing valleys by laying one shingle over the other up the valley center